Unit Conversion Guide
Unit conversion is about changing the same quantity into a different unit without changing its value. The key idea is to multiply by a conversion factor that keeps the measurement equivalent.
How to convert
- Identify the unit you have and the unit you want.
- Use the correct conversion factor, such as 1000 m = 1 km or 100 cm = 1 m.
- Multiply if converting to a smaller unit and divide if converting to a bigger unit.
- Check your answer makes sense: a bigger unit should give a smaller number.
Example: Convert 450 cm to metres.
1 m = 100 cm, so 450 ÷ 100 = 4.5 m.
1 m = 100 cm, so 450 ÷ 100 = 4.5 m.
Example: Convert 3.2 kg to g.
1 kg = 1000 g, so 3.2 × 1000 = 3200 g.
1 kg = 1000 g, so 3.2 × 1000 = 3200 g.
Quick rules
- To go from larger units to smaller units: multiply.
- To go from smaller units to larger units: divide.
- For a full prefix table from pico to tera, see the separate power-of-10 guide.